Heading into the 2004 season, recently acquired White Sox player Mark Teahen was a 22-year-old Oakland A's prospect with just one full season under his belt. Most players in similar situations are able to toil in relative anonymity, but then again, most players hadn't received a prominent mention in one of the most widely discussed sports books of our time.

The book in question was Michael Lewis' Moneyball, which detailed the unorthodox front office strategies of A's general manager Billy Beane. In one pivotal scene, Lewis describes a contentious conversation between Beane and his veteran scouts regarding Teahen's merits as a player. Beane's view was that the St. Mary's product was a natural hitter with a tremendous upside, one perhaps capable of reaching the lofty heights of Jason Giambi. The scouts were considerably less enthused, not at all convinced that Teahan's collegiate success would translate to the professional ranks.

Beane prevailed, of course, and the A's selected Teahen as a supplemental first-round pick in the 2002 Draft. The next year, he played his first full professional season as a member of the Modesto A's in the Class A Advanced California League.

"At that stage in his career, he had a tendency to hit the ball the other way," recalled Rick Rodriguez, who managed the '03 Modesto club. "So we worked with him a lot, trying to get him to pull more. But he was a great line-drive hitter and could always drive the ball in the gap. He made solid contact, knew the strike zone, and put together great at-bats day in and day out."

But even more important were Teahen's intangibles.

"He was a quiet guy, but very intense, and always hustling," said Rodriguez, currently the pitching coach for the Triple-A Sacramento River Cats. "He was one of the more aggressive guys out there and one of the best defensive third basemen I had ever seen at that level."

Moneyball was released in December 2003, making the A's internal dissent regarding Teahen public knowledge. And if Teahen was affected by the unexpected publicity, he didn't let on. He began the season by hitting .335 over 53 games with Double-A Midland and then received a promotion to Sacramento. After 20 games there, Teahen was traded to the Kansas City Royals organization as part of a three-team, five-player trade (the centerpiece of the deal was Carlos Beltran, who relocated from Kansas City to Houston). Teahan's first (and only) stop as a Kansas City farmhand was Triple-A Omaha, where manager Mike Jirschele was more than happy to have him.

"It was exciting, having him come over. [The Royals] had to give something up, but it was definitely worth it," said Jirschele, who has managed the O-Royals for the past seven seasons. "Guys would give him a hard time because of [Moneyball], but he just joked about it, like 'I'm in a book already, and haven't even played in the big leagues.' But that's the thing with Mark. When he faces adversity, he doesn't collapse. He just keeps going, figuring out a way to win, and that's one thing you can't teach players.

"Mark's a jokester, with a real dry sense of humor," added Jirschele. "He'll crack a joke and not even smile, so you won't even know if he's joking or not. He was a lot of fun in the clubhouse, keeping everybody loose, and those are generally the type of guys that are leaders in the field."

With Omaha in 2004, Teahan hit .280 with eight home runs and 31 RBIs over 66 games. He was expected to return to the club in 2005, but he ended up making Kansas City's Opening Day roster after third basemen Chris Truby and Chris Clapinski suffered injuries.

"At that point, maybe he could have used a little more time [in the Minor Leagues], but [the Royals] had to make a move and they felt that Mark was mature enough to deal with the ups and downs and keep going," said Jirschele.

While he has not lived up to the burdensome "next Giambi" designation placed upon him in Moneyball, Teahen has indeed proved himself capable of playing in the Major Leagues. The 28-year-old has accumulated 667 hits over the past five seasons while logging time at third base, second base and right field. And throughout, he has kept up the tenacious, hard-nosed style of play that first endeared him to his Minor League coaches.

"Since day one, I've been a fan," said Rodriguez. "I still am. I try to watch him whenever I can."

Minor League career breakdown

2002: After being selected by the A's as a supplemental first-round Draft pick, Teahen was sent to Class A Short-Season Vancouver. After hitting .404 over 13 Northwest League games, he received a promotion to Class A Advanced Modesto, where he hit .234 over 59 games.

2003: Playing his first full season at the age of 21, Teahen hit .278 and drove in 58 runs over 103 games with the Modesto A's. He hit a respectable 20 doubles in 381 at-bats, but managed to go yard just twice.

2004 : After tearing through Texas League pitching as a member of Double-A Midland (.335, 36 RBIs, 31 runs in 53 games), he received a promotion to Triple-A Sacramento (.275 over 20 games). Soon thereafter, he was traded to Kansas City and assigned to Omaha. There, he hit .280 with eight home runs, 33 runs and 31 RBIs over 66 games.

This story was not subject to the approval of the National Association of Professional Baseball Leagues or its clubs.